I've listed a more detailed description of this in the feature request section, but can't help thinking it's a bug, so i'm listing it here too:
The sequencer knobs cannot be assigned to the programmable matrix columns 13-16, which it strange as the manual states that can be controlled with CC values just as all other knobs that can assigned.
It's a real pity as being able to control the rate of the sequencer with an envelope would create some very interesting effects